EXCHANGE QUESTIONS
|
EXCHANGE QUESTIONS |
|||
| The micrograph below of a fish's gill clearly shows the secondary lamellae arranged at 90degrees to the gill filaments | |||
|
|
|||
| a | i | Using information from the micrograph explain why the structure of the gills make them efficient at exchanging gases between blood and water | |
| (4) | |||
| ii | The flow of blood and water through the secondary lamellae is often described as countercurrent. Explain the significance of this in relation to gas exchange | ||
| (2) | |||
| b | Name the structure labelled X in the diagram below | ||
|
|
|||
| (1) | |||
|
|
|||